Safety knee assemblage with adjustable means for increasing or decreasing clearance between braking surfaces



H. O. M. NADER ETAL March 21, 1967 SAFETY KNEE ASSEMBLAGE WITH ADJUSTABLE MEANS FOR INCREASING OR DECREASING CLEARANCE BETWEEN BRAKING SURFACES Filed Dec. 30

2 Sheets-Sheet l SAFETY KNEE ASSEMBLAGE WITH ADJUSTABLE MEANS OR DECREASING CLEARANCE BETWEEN BRAKING SURFACES Filed Dec.

United States Patent Office 3,369,715 Patented Mar. 21, 1967 SAFETY KNEE ASSEIVBLAGE WITH ADJUST- ABLE MEANS FOR INCREASING (3R DE- CREASING CLEARANCE BETWEEN BRAK- ING SURFACES Hugo Qtto Max Nader, Dnderstadt, Hannover, and Werner Haupt, Duderstadt-Tiftlingerode, Germany, assignors to Gtto Bock Orthopedic Industry, Inc., Minneapolis, Minn, a corporation of Minnesota Filed Dec. 30, 1963, Ser.'No. 334,091 14 Claims. (C1. 327) This invention relates generally to prosthetic devices, and pertains more particularly to a safety knee for artificial legs.

Safety knees, such as the general type with which the present invention is concerned, are not completely new. However, the safety knees that have been marketed up to the present time have been unduly complicated and have contained a large number of components or parts. Accordingly, an object of the instant invention is to reduce the number of components or parts and thus provide a safety knee that is considerably less complicated than those of the prior art.

Another object of the invention, which follows directly from the preceding object, is to provide a safety knee that is lighter in weight than the more complicated prior art knees.

Another object of the invention is to provide a safety knee that is very simple and thereby easily manufactured and also readily serviced when circumstances so dictate, although the need for servicing is appreciably minimized with the envisaged construction.

A further object of the invention is to provide a safety knee having breake surfaces that can be more readily adjusted in order to compensate for wear and also for various specific tasks that the amputee may wish to perform. With respect to the former, there will be a gradual wear of the brake linings and the present invention permits the knee to be adjusted for whatever Wear may occur. On the other hand, there are certain tasks that necessitate a more abrupt adjustment and which adjustment should be performed in an inconspicuous manner. Therefore, the invention has for an aim the adjustment of the braking surfaces through the users clothing in order to either decrease or increase the clearances between the brake surfaces. In this regard, the brake surfaces can be adjusted so as to provide sufficient clearance in order to permit complete freedom of movement, such movement being desirable when riding a bicycle, for instance. If the amputee desires a completely rigid knee, such adjustment can also be achieved, this permitting the user to walk on uneven ground, for instance. Consequently, the present invention provides a considerable amount of versatility as far as the adjustment feature is concerned.

A still further object is to provide a safety knee that will not be adversely affected to any noticeable extent by changes in humidity, thereby avoiding any need for making adjustments due to atmospheric change.

Yet another object of the invention is to provide an improved knee axis brake, it being within the contemplation of the invention to employ larger braking areas without increasing the size of the components or parts, thereby providing a longer-lasting knee axis brake.

These and other objects and advantages of my invention will more fully appear from the following description, made in connection with the accompanying drawings, wherein like reference characters refer to the same or similar parts throughout the several views and in which:

FIGURE 1 is a fragmentary view from one side of a safety knee constructed in accordance with the teachings of the present invention, the view depicting the knee with the amputees weight placed thereon;

FIGURE 2 is a sectional vie-w taken in the direction of line 2-2 of FIGURE 1;

FIGURE 3 is a view generally similar to FIGURE 1 but illustrating the knee when little or no weight is placed thereon;

FIGURE 4 is a View taken from the left in FIGURE 3;

FIGURE 5 is a sectional view taken in the direction of line 5-5 of FIGURE 4, and

FIGURE 6 is a sectional view taken in the direction of line 6-6 of FIGURE 5.

Referring now in detail to the drawings, the safety knee assemblage illustrating the present invention has been designated generally by the reference numeral 10. This assemblage includes a knee or upper member 12 having a notch 14 at the rear which provides a pair of downwardly extending spaced sides 15. The notch 14 also forms a roof or upper surface 16 and a floor or lower surface 17 as best seen in FIGURE 4. The knee assemblage further includes a hollow shin or lower member 18 which is also notched at the rear indicated by the reference numeral 20 to provide upwardly extending spaced sides 22.

Fixedly embedded in opposite sides of the shin member 18 are metal braces 24, 26. As can best be seen from FIGURE 2, the metal brace 24 has a threaded aperture 28, whereas the brace 26 has an unthreaded aperture 30.

A knee bolt 32 has its opposite ends received in the apertures 28, 3%. More specifically, the knee bolt 32 includes a head 34 and there is an externally threaded portion 36 adjacent said head 34. The opposite end of the bolt 32 is provided with internal threads at 38. The internal threads 38 accommodate a bolt screw 40 having a head 42, the threaded shank labeled 44! being received into the threads at 38. From FIGURE 2, it will be dis-. cerned that the sides 15 of the knee member 12 are formed with circular apertures at 46. Pressfitted within these apertures 46 are fiber liners 48 having oblong openings or bores 50 for a purpose presently to be described.

As can best be seen from FIGURE 6, the knee member 12 is formed with a V-shaped notch 52, the sides of which are lined with leather braking segments 54. Coopera-ble with the braking segments 54 is a V-shaped wedge 56 that is fixedly carried by the shin member 18. Thus, the tapered sides of the V-shaped wedge 56 are engageable with the segments 54- lining the V-shaped notch 52. The braking action provided by the segments 54 will be better understood from a more detailed description of the opeartion that will be presented hereinafter. However, at this time, attention is directed to a pair of resilient shock absorbers or cushions 58 and 69, the cushion 58 being appropriately adhered to the upper end of the V-shaped notch 5-2 and the cushion 60 being appropriately adhered to the upper end of the V-shaped wedge 56. These elements are depicted in phantom outline in FIGURE 5, although a portion of the cushion 60 appears in solid outline where it is visible.

Playing an important role in the practicing of the present invention is a swing block 6-2 of tough plastic material, such as phenolic resin. The block 62 is provided with a first transverse aperture 64 for the accommodation of a plastic pivot pin 66 having its ends received in a pair of fiber bushings 68, '70 located in a pair of cylindrical openings 72 formed in the downwardly extending sides 15 of the knee member 12. It will be perceived that the bushing 68 has an unobstructed bore at 74 which permits the pin to be forced into position, whereas the bushing 79 has a smaller knock-out aperture 76 so that the pin 66 can be replaced should circumstances so dictate.

Continuing with the description of the swing block 62, it will be further noted that this block is provided with a second transverse aperture 78 which encircles the knee bolt 32. As can be best understood from EEG- UR-E 5, the block 62 is formed with a transverse groove 80. From FIGURE 5, as well as FIGURE 2, it will be seen that the groove has received therein a brake shoe strip 82 and a pressure plate 84. Through the agency of a pair of screws or plugs 86, plus a pair of threaded apertures 38 having therein a pair of adjusting screws 90, pressure can be applied to the screws 35 so as to urge the pressure plate 84 and the brake shoe strip 82 against the knee bolt 32 to provide a braking action about the axis of the knee when the knee is bent or pivoted from the position shown in FIGURE 1 to that pictured in FIGURE 3. A notch 92 formed in the block 6;. permits even a greater angular movement than that shown between the views of FIGURES l and 3, inasmuch as the knee bending can be realized for extreme angles without interference between the V-shaped wedge 56 and the swing block 62.

At this time, attention is directed to a pair of compression spring recesses 94 provided in the swing block 62 intermediate the transverse apertures 64 and 78, the recesses extending at right angles to the plane which includes the axes of said transverse apertures. Contained within each recess 94 is a compression spring 96 which acts against the underside of a flanged plug 98. The spring action provided by the springs 96 normally causes the plugs 8 to bear against the roof 16 provided by the notch 14 in the knee member 12. Stated somewhat ditferently, the role performed by the springs 96 is to bias the swing block 62 in a counterclockwise dircction about pivot pin 66 as viewed in FIJURE 5.

It will be recalled that leather braking segments 54 are disposed in the V-shaped notch 52 and that these segments coact with the V-shaped wedge 56. For the purpose of regulating the degree of braking action produced between the segments 55 and the sides of the wedge 56 is a regulator, more specifically, a special screw referred to below. First, it will be pointed out that the swing block 62 contains a threaded aperture 1% which is countersunk at 1112. This aperture Hit) permits the accommodation of a brake distance regulating screw indicated generally by the reference numeral 164-, the screw 194 controlling or regulating the degree of braking action in a manner now to be described. The screw 104 has an integral knurled head 186 that is sufficiently large in area in order to provide a well-distributed pressural action or loading against the roof 16 under certain operating conditions. The screw 1% includes a threaded shank 168 that is engaged with the aforenoted threaded aperture 160. Further, the screw 18% has a projecting flange end 116 that provides an adequate bearing surface for engagement with the floor 17. Thus, either the head 1% can be manipulated so as to abut the roof 16 or the flange 11% can be manipulated so as to abut the fioor 17, such action being derived by merely turning the regulating screw 1134-. The actual functioning of the regulating screw 104, however, will be better comprehended when considered in conjunction with the ensuing operational sequence.

With continued reference to the swing block 62, it is to be noted that this block contains still a third transverse aperture 112. Extending through the aperture 112 is a pin 114 having projecting ends. The projecting ends provide pivotal connection with a forward bow denoted generally by the reference numeral 116. cludes a pair of upwardly extending parallel arms 11-8 having apertures 120 at their upper extremities. A cross piece or bridging portion 122 extends between the lower end of the arm 118 and carries a resilient cushion 124 which functions as a deceleration stop inasmuch as it is located so as to strike the underside of the V-shaped wedge 56 when the members 12, 18 are in the position pictured in FIGURE 1. Further included as elements of the bow 116 are a pair of laterally spaced ears 126 having arcuate notches 12% therein. The notches 123 engage a glide piece 130, having contact with a pair of transverse ribs 132. Hence, the glide piece 13% can rock relative to the ears 126. The glide piece 136 is formed with a central aperture for the accommodation of a guide bolt 134 that extends upwardly therethrough. The lower end of the guide bolt 134 is equipped with an integral flange or head 136. The guide bolt 134 additionally includes a shank 133, this being the portion of the guide bolt that extends through the glide piece 130, and at the upper end of the shank 138 is a threaded portion 140 having a screwdriver slot 142 extending thereacross. The upper end 141 of the guide bolt 134 is threadedly received in a guide bolt bushing or sleeve 144 having a flanged upper end 146 and internal threads 148 which actually effect the threaded engagement with the end 140 of the bolt 134. As can be clearly seen in FIG- URE 5, the shin member 18 has formed therein an aperture 150 which is countersunk at 152 to form a shoulder which limits downward movement of the bushing 144; the bushing 144 is pressfitted within the aperture 150 so as to be fixedly retained within the confines of the member 18. Still further, there is included a coil spring 154 that is interposed between the glide piece 135 and the flange or head 136 on the lower end of the guide bolt 134. When free to do so, the spring 154 of the forward bow 116 acts in a direction so as to urge the members 12, 18 into the relationship depicted in FIGURE 1.

Having presented the foregoing information, the manner in which my safety knee is used and the way in which it functions should be readily apparent. However, a brief operational description should be of assistance in appreciating the various benefits an amputee derives when utilizing a prosthetic device of the character described.

Initially, the user adjusts the forward bow 116 in order to regulate the forward motion of the shin member 18, such adjustment of course also governing the rate at which the shin is brought back preparatory to taking a step. This is done by turning the guide bolt 134', with a screwdriver inserted in the slot 142. It will be apparent that rotating the guide bolt 134 determines the degree of compression of the coil spring 154, which determines the above-alluded to regulation.

Interrelated with the functioning of the forward bow 116 is the braking action supplied by the strip '82, for the strip 82 imposes a frictional drag on the knee bolt 32. This frictional drag can be adjusted via the adjusting screws 9%, since these screws act on the pressure plate 84. Owing to the relatively large braking surface supplied by the strip 82, the screws 90 will not require frequent adjustment as the wear will not be great even for relatively long periods of usage.

Assuming that the regulating screw is approximately in the position shown, when the amputee takes a step the oblong openings 50 in the fiber liners 48 will allow the leather braking segments 54 to press against the V-shaped wedge 56. These braking surfaces 54, 56 are always in a sliding contact due to the counterpressure of the forward how 116 on the swing block 62. for the particular setting of the regulating screw 164 that has been illustrated. Stated more specifically, the swing block 62, as

The bow 116 inviewed in FIGURE 5, is urged in a clockwise direction about the pin 66 by the forward how 116, being automatically biased in this direction by the spring 154. Since the knee bolt 32 fits snugly in the transverse aperture 78 (see FIGURE 6), but not in the fiber liners 48 (see also FIGURE 6 as well as FIGURES 1 and 2), such a biasing force is transmitted to the braces 24, 26 because the knee bolt 32 is threadedly supported thereon. This pulls the wedge 56 and braking segments 54 toward each other due to the fact that the braces 24, 26 are fixedly attached to the lower member 18. In this way a gliding contact is established between the wedge 56 and the segments 54. Consequently, when weight is applied to the upper member 12, as when taking a step, there is no clearance to be taken up. Yet as the user applies more weight the braking action between the segments 54 and its wedge will increase to provide a more natural stride. Although the action of the spring 154 of the forward how 116 will change slightly with humidity changes, as will the coeflicient of friction of the segments 54, there is no need for the user to have to adjust the regulator screw 104. However, when the segments or lining 54 become worn sufliciently, an adjustment can be easily made with the regulator screw 104 to mtaintain the desired gliding contact.

If the pressural engagement between the elements 54, 56 is to be increased, then the screw 104 is rotated by the user in a direction to cause the lower end thereof to react against the floor 17 0f the notch 14. Sufficient movement of the screw in the mentioned direction can be utilized to render the knee completely stiflF, such as for walking on uneven ground. Of course, during normal usage there will be a gradual Wearing taking place with respect to the leather braking segments and this wear can be compensated for by merely adjusting the screw 104 as mentioned above. Should the user desire to eliminate completely the braking effect, the screw 104 can be turned in a reverse direction to the extent that the head abuts the roof 16 of the notch 14, thereby preventing any contact of the leather segments 54 with the wedge 56, such as would be desired when the amputee rides a bicycle or drives an automobile.

Thus, it can be appreciated that these are two extreme positions of the regulating screw 104, one in which the knee assemblage is made completely stiff and the other where the assemblage is made completely free*. In between these positions, various degrees of adjustment can be achieved with respect to the amount of braking action developed and the compensation for brake wear.

It will, of course, be understood that various changes may be made in the form, details, arrangements and proportions of the parts without departing from the scope of our invention.

What is claimed is:

1. A safety knee assemblage comprising:

(a) an upper member;

(b) a lower member;

(c) a knee bolt pivotally connecting said members together to form a knee joint;

(d) a swing block pivotally connected near one end of a lower portion of said upper member,

(e) resilient means connected near the other end of said swing block and to said lower member for urging said members into a desired pivotal relationship with each other;

(f) said swing block having an aperture extending therethrough receiving said knee bolt;

(g) means for braking the pivotal movement of said members with respect to each other, and

(h) regulating means carried on said swing block and extending downwardly through said block for engaging a portion of said upper member for controlling the action of said braking means.

2. A safety knee assemblage in accordance with claim 1 in which:

(a) said braking means includes relatively slidable surfaces on said members, and

(b) said regulating means includes a screw for relatively urging said surfaces toward each other to increase the braking action of said braking means.

3. A safety knee assemblage in accordance with claim 1 in which:

(a) said swing block is formed with a transverse groove communicating with said aperture, and

(b) a brake shoe strip disposed in said groove for engaging said knee bolt.

4. A safety knee assemblage in accordance with claim 3 including:

(a) means for adjusting the pressural action of said brake shoe strip.

5. A safety knee assemblage in accordance with claim 4 in which said adjusting means includes:

(a) a pressure plate, and

(b) a pair of laterally spaced screws threadably carried on said swing block for forcing said pressure plate against said brake shoe strip.

6. A safety knee assemblage comprising:

(a) an upper member;

(b) a lower member;

(c) a knee bolt pivotally connecting said members together to form a knee joint;

(d) a swing block pivotally connected near one end to a lower portion of said upper member,

(e) a resilient bow mechanism pivotally connected to said swing block near the other end thereof and slidably connected to said lower member for normally urging said members into a desired pivotal relation with each other,

(f) said swing block having an aperture through which said knee bolt extends;

(g) respective means on said members providing relatively movable braking surfaces, and

(h) a regulating screw threadedly mounted on said swing block and extending downwardly therethrough, said screw having its lower end thereof reactively engageable with said means on said upper member for adjusting the degree of braking action between said surfaces.

7. A safety knee assemblage in accordance with claim 6 in which:

(a) the upper end of said regulating screw is reactively engageable with a portion of said upper member to prevent contact between said braking surfaces.

8. A safety knee assemblage comprising:

(a) an upper member;

(b) a lower member;

(c) a knee bolt having its ends anchored to side portions of said lower member;

(d) side portions of said upper member having openings therein of a size to allow said knee bolt to loosely pass therethrough;

(e) a swing block pivotally connected adjacent one end of said upper member,

(f) said swing block having a transverse aperture intermediate its ends for encircling said knee bolt; (g) a spring biased bow having its upper end pivotally connected adjacent the other end of said swing block and having its lower end slidably connected to said lower member for urging said lower member into a preferred angular relationship with said upper member through the agency of said swing block;

(b) complementally tapered braking surfaces on said members, and

(i) a downwardly extending regulating screw threadably carried on said swing block for swinging said block in opposite directions to increase or decrease the clearance between said braking surfaces.

9. A safety knee assemblage comprising:

(a) an upper member having downwardly extending spaced sides forming a notch therebetween;

(b) a lower member having upwardly extending spaced sides for overlying the outer surfaces of said firstrnentioned sides;

(0) a knee bolt having its ends received in said secondmentioned sides;

(d) said first-mentioned sides having openings therein through which said knee bolt extends;

(e) a swing block disposed in said notch;

(f) a pivot pin having its ends connected to said firstmentioned sides and extending through a portion 7 of said swing blocknear one end thereof to mount said swing block for vertical pivotal movement;

(g) said swing block having a transverse aperture intermediate its ends receiving said knee bolt;

(h) a resilient bow mechanism pivotally connected to said swing block near the other end thereof and slidably connected to said lower member for biasing said lower member into a substantially straight line relationship with said upper member;

(i) a first braking surface on said upper member;

(j) a second braking surface on said lower member;

(k) a regulating screw threadedly mounted on said swing block at a point between said transverse aperture and the point where said bow mechanism is connected, one end of said regulating screw being engageable with a portion of said upper member to cause said braking surfaces to be moved toward each other when said regulating screw is rotated in one direction.

10. A safety knee assemblage in accordance with claim 9 in which: 7

(a) said openings in said first-mentioned sides are of a size to provide sufficient clearance with said knee bolt so as to allow greater relative movement of said braking surfaces when said regulating screw is rotated. 11. A safety knee assemblage in accordance with claim 19 in which:

(a) the braking surface on said upper member is in the form of an inverted V-shaped notch and the braking surface on said lower member is in the form of a V-shaped wedge.

12. A safety knee assemblage in accordance with claim 11 in which:

o (a) the other end of said regulating screw is engageable with the roof the notch between said firstmentioned sides when said regulating screw is rotated in an opposite direction. 13. A safety knee assemblage in accordance with claim 12 including:

(a) spring means interposed between said swing block and said roof for moving said blocks away from said roof.

14. A safety knee assemblage in accordance with claim 13 in which:

(a) said swing block is formed with a transverse groove communicating with said aperture;

(b) a brake shoe strip disposed in said groove for 15 engaging said knee bolt, and

(c) means for adjusting the pressural action of said brake shoe strip.

References Cited by the Examiner UNITED STATES PATENTS 692,360 2/1902 Rowley 328 744,801 11/1903 Rowley 3-28 FOREIGN PATENTS 949,003 9/1956 Germany.

OTHER REFERENCES I. W. Edwards, Artificial Limbs. In Orthopaedic Appliances Atlas, Ann Arbor, Mich., vol. 2, 1960, pages 199-200, Figure 5.94.

RICHARD A. GAUDET, Primary Examiner.

R. L. FRINKS, Assistant Examiner. 

1. A SAFETY KNEE ASSEMBLAGE COMPRISING: (A) AN UPPER MEMBER; (B) A LOWER MEMBER; (C) A KNEE BOLT PIVOTALLY CONNECTING SAID MEMBERS TOGETHER TO FORM A KNEE JOINT; (D) A SWING BLOCK PIVOTALLY CONNECTED NEAR ONE END OF A LOWER PORTION OF SAID UPPER MEMBER, (E) RESILIENT MEANS CONNECTED NEAR THE OTHER END OF SAID SWING BLOCK AND TO SAID LOWER MEMBER FOR URGING SAID MEMBERS INTO A DESIRED PIVOTAL RELATIONSHIP WITH EACH OTHER; (F) SAID SWING BLOCK HAVING AN APERTURE EXTENDING THERETHROUGH RECEIVING SAID KNEE BOLT; (G) MEANS FOR BRAKING THE PIVOTAL MOVEMENT OF SAID MEMBERS WITH RESPECT TO EACH OTHER, AND (H) REGULATING MEANS CARRIED ON SAID SWING BLOCK AND EXTENDING DOWNWARDLY THROUGH SAID BLOCK FOR ENGAGING A PORTION OF SAID UPPER MEMBER FOR CONTROLLING THE ACTION OF SAID BRAKING MEANS. 